NASA Technical Memorandum 4411 Computational Parametric

A computational parametric study of three-dimensional, sidewallcompression scramjet inlets was performed to identify the e ects of geometric parameters on inlet performance. The parameters were the leadingedge sweep angle, varied between 30 and 60 , and the leading-edge position of the cowl, located at the throat and at two forward positions. A laminar boundary layer with cold-wall (T wall = 300 K (540 R)) boundary conditions was imposed. The parametric study was performed for a Mach number of 10 and a unit free-stream Reynolds number of 7.06 10 6 per meter (2.15 10 6 per foot) at a geometric contraction ratio of 5. The performance of each con guration was evaluated in terms of the mass capture, throat Mach number, total pressure recovery, kinetic energy e ciency, and internal compression. One computation of an unswept con guration was included as a baseline to determine the e ects of introducing leading-edge sweep on the oweld parameters. The purpose of the computational parametric study was to perform a trade-o of the e ects of various geometric parameters on the global performance of the inlet. Although no single optimal con guration emerged, trade-o s among the stated performance parameters identi ed a leading-edge sweep angle of 45 as possessing the most attractive performance characteristics.